Biciliated ependymal cell proliferation contributes to spinal cord growth

Abstract

Two neurogenic regions have been described in the adult brain, the lateral ventricle subventricular zone and the dentate gyrus subgranular zone. It has been suggested that neural stem cells also line the central canal of the adult spinal cord. Using transmission and scanning electron microscopy and immunostaining, we describe here the organization and cell types of the central canal epithelium in adult mice. The identity of dividing cells was determined by three-dimensional ultrastructural reconstructions of [3H]thymidine-labeled cells and confocal analysis of bromodeoxyuridine labeling. The most common cell type lining the central canal had two long motile (9+2) cilia and was vimentin+, CD24+, FoxJ1+, Sox2+ and CD133+, but nestin- and glial fibrillary acidic protein (GFAP)-. These biciliated ependymal cells of the central canal (Ecc) resembled E2 cells of the lateral ventricles, but their basal bodies were different from that of E2 or E1 cells. Interestingly, we frequently found Ecc cells with two nuclei and four cilia, suggesting they are formed by incomplete cytokinesis or cell fusion. GFAP+ astrocytes with a single cilium and an orthogonally oriented centriole were also observed. The majority of dividing cells corresponded to biciliated Ecc cells. Central canal proliferation was most common during the active period of spinal cord growth. Pairs of labeled Ecc cells were observed within the central canal in adult mice 2.5 weeks post-labeling. Our work suggests that the vast majority of postnatal dividing cells in the central canal are Ecc cells and their proliferation is associated with the growth of the spinal cord.

Developmental localization of adhesion and scaffolding proteins at the cone synapse

“…β-catenin: The β-catenin antibody used in this study detects a band of 92 kDA in lysates of HeLa cells and the protein localizes to cell boundaries (manufacturer's website). Consistent staining patterns with other bcatenin antibodies in spinal cord was also reported (Alfaro-Cervello et al, 2012). MAGI2 : The MAGI2 antibody used in this study recognizes a bands of 180, 160 and 105 kDA and does not cross react with related molecules.…”

Nestin-Positive Ependymal Cells Are Increased in the Human Spinal Cord after Traumatic Central Nervous System Injury

“…For example, Meletis and associates 5 identified three distinct ependymal cell populations in the mouse central canal 1 based on morphological differences, but was unable to determine any molecular marker delineating these subpopulations. AlfaroCervello and associates 22 described biciliated ependymal cells of the central canal that are nestin positive and glial fibrillary acid protein (GFAP) negative, and which proliferate slowly under normal growth conditions. Dromard and associates 17 indicated a cluster of nestin-positive cells located in the ventral subependymal region as being a possible neurogenic niche, whereas Hamilton and associates 8 reported that cells with stem cell characteristics may be located in the dorsal pole of the central canal and have a tanycytelike morphology.…”

Spinal Cord Ependymal Responses to Naturally Occurring Traumatic Spinal Cord Injury in Dogs

“…3,28,30,38 In vitro, cells from the SEL of both mice and humans can also assume stem cell properties, generating multipotent neurospheres in culture. 1,7,28 Given these findings, experimental treatments that exploit the SEL as a source of endogenous neural stem cells are currently being explored in rodent models of SCI, with some success. 32 However, as with other promising treatments for SCI, translation from rodent models to human patients will present a challenging next step.…”